Comey fired; Snap earnings; Barclays CEO under pressure

Comey was responsible for the bureau's investigation into whether members of Trump's campaign team colluded with Russia in its interference in last year's election.

Markets did not register a major reaction to the shock development. The dollar slipped 0.2% against major currencies, but recovered overnight. U.S. stock futures were slightly lower early Wednesday, a move broadly in line with global markets.

2. Snapchat earnings: Snap(SNAP) will release its first earnings report as a public company on Wednesday. The tech firm is expected to post a loss and analysts are skeptical that it can gain a lot more users now that Facebook(FB) and Instagram have copied many of its features.

The stock has already lost all of its post-IPO gains.

3. Barclays under pressure:Barclays(BCS) CEO Jes Staley is likely to come under pressure from shareholders during the bank's annual meeting Wednesday.

Staley admitted last month that he had attempted to unmask a whistleblower.

The incident is being investigated by regulators in the U.K. and U.S.

ISS, which advises major shareholders, has recommended investors not vote in favor of Staley's reelection to the bank's board.